Adult colocolic intussusception diagnosed by ultrasonography: a case report

INTRODUCTION: Intussusception is highly uncommon in adults and accounts for only 5% of all reported cases. It is more commonly secondary to an identifiable bowel lesion in 90% of cases, whereas 10% have no discernable cause. Diagnosis is difficult due to non-specific symptoms of the disease. Diagnostic imaging plays an important role in the diagnosis of the condition. Sonography and computed tomography are the most commonly used imaging techniques. In adults, intussusception usually requires treatment by surgical resection of the affected bowel. CASE PRESENTATION: A 35-year-old Moroccan woman presented with a five-month history of intermittent abdominal pain and one episode of bleeding from the rectum. At physical examination an abdominal mass was noted. Abdominal sonography revealed a 6.3 × 8.5 cm midline mass in her upper abdomen that was tender. In transverse section, the mass had the multiple concentric rings of hypoechoic and echogenic layers associated with the sonographic appearance of intussusception. In longitudinal section, the mass had the sonographic aspect of multiple parallel lines, giving the so-called "sandwich appearance". A corresponding contrast-enhanced abdominal computed tomography scan also demonstrated the intussusception. Surgery confirmed a colocolic intussusception with a large, firm, indurated mass as the lead point. A right hemicolectomy was undertaken because of concern about possible malignancy. The resected ascending colon was then opened up, to find a protruding tumor of the ascending colon that was acting as the lead point. It measured 7.6 × 6.9 × 2.4 cm. Pathology diagnosed an infiltrating, differentiated adenocarcinoma of the ascending colon invading through the muscularis propria. No lymphovascular invasion was seen. Our patient has recovered well. CONCLUSION: Intussusception is relatively rare in the adult population, and this, along with the vague clinical features, makes diagnosis difficult. Ultrasonography and computed tomography have been proven to be effective diagnostic modalities. Ultrasonography can be performed quickly and accurately, and is widely available. In adults, intussusception is usually associated with an underlying cause and requires treatment by surgical resection.